Answer:
x=5, y=-3
Step-by-step explanation:
we can find the answer by plugging in x=3y+14 to the second equation
5(3y+14)-2y=31
simplify
15y+70-2y=31
13y=-39
y=-3
now, plug in this to the initial equation x=3y+14
x=3(-3)+14
x=-9+14
x=5
Answer: The equation of an ellipse:
(
x
−
h
)
2
a
2
+
(
y
−
k
)
2
b
2
=
1
;
a
>
b
Has vertices at
(
h
±
a
,
k
)
Has foci at
(
h
±
√
a
2
−
b
2
,
k
)
Use the vertices to write 3 equations:
k
=
4
[1]
h
−
a
=
−
6
[2]
h
+
a
=
10
[3]
Use equations [2] and [3] to solve for h and a:
2
h
=
4
h
=
2
a
=
8
Use the focus to write another equation:
8
=
h
+
√
a
2
−
b
2
Substitute values for h and a:
8
=
2
+
√
8
2
−
b
2
6
=
√
64
−
b
2
36
=
64
−
b
2
b
2
=
64
−
36
b
2
=
28
b
=
√
28
Substitute the values into the standard form:
(
x
−
2
)
2
8
2
+
(
y
−
4
)
2
(
√
28
)
2
=
1
To find the inverse of this function, we first need to replace f(x) with y.
y = 2x^2 + 3
Now, we swap x and y
x = 2y^2 + 3
Now, we solve for y.
-3
x - 3 = 2y^2
Sqrt both sides.
√(x - 3) = 2y
Divide by 2
√(x - 3)/2 = y
Replace y with f^-1(x)
√(x - 3)/2 = f^-1(x)
Just realized you were asking for f(-1), not f^-1(x)
Feels bad.
f(-1) = 2(-1^2 + 3)
f(-1) = 2(-1^5)
f(-1) = 2(-1)
<u>f(-1) = -2</u>
I'm leaving the original answer in case you also need the inverse function. :)
